The prevalence of skin cancer is increasing worldwide, with epidemic levels present in North America, Europe and Australia. For example, skin cancer is the most common cancer in the United States with over 3.5M million annual cases. Statistics from the American Cancer Society indicate that 20% of the American population will develop this disease during their lifetime.
Skin cancer is unusually complex and difficult to diagnose, and current clinical practice relies on highly subjective visual methods for detection. Presently, visual inspection by a dermatologist has good sensitivity (>90%) but poor specificity (<10%), especially for melanoma, which leads to a high number of unnecessary biopsies. Further, it is estimated that dermatologists miss about one third of curable melanomas, which is the most deadly form of skin cancer. Missing a curable melanoma delays treatment and can lead to metastatic cancer, which has a five-year survival rate of less than 15%, and it can cost upwards of $170,000 per case to treat compared to $1,800 in the case of lesion-removal surgery if caught early. Physicians have employed noninvasive skin-cancer screening and diagnostic aids with limited success because most of them do not provide substantial improvements in diagnostic accuracy beyond the existing visual methods.
It is estimated that about 10.6 million excess skin cancer biopsies are done in the United States (US) per year. If the laboratory and medical doctor (MD) payment rate for Medicare (Code 88305=$70 for laboratory and Code 11100=$90 for MD) is considered, the 100% addressable U.S. market for excess skin biopsies is around $1.7B/year. Further, the yield of skin cancer biopsies performed to diagnose cancer is quite low, with 30 benign lesions biopsied for every one melanoma, and three benign lesions biopsied for each non-melanoma skin cancer such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). In addition to the cost burden to payers, the excess biopsies are a source of patient discomfort, which may discourage patients from seeking help from a specialist.
The medical community has been pursuing non-invasive and early detection of skin cancer based on thermal imaging. One of the approaches is to make a decision whether the lesion is benign or malignant based on a sequence of thermal-images obtained of the lesion after it is cooled substantially, then removing the cooling source and allowing the tissue to naturally warm up back to the body temperature.
Improved skin cancer detection methods, and systems for performing the improved methods, would be desirable.